The primary objective of this work is to develop a proteomic analysis method and demonstrate its utility for economical diagnosis of Celiac Disease, a common autoimmune digestive disorder associated with intolerance to gluten present in wheat, barley, and rye grains. In addition, this work is expected to lead to a better understanding of the cause of Celiac Disease. This work will result in the identification large panel of peptide ligands that can serve as an inexpensive but comprehensive diagnostic reagent panel for Celiac Disease. These peptides will be identified using a new molecular screening methodology. Briefly, this project will involve i) fluorescent- labeling of serum components from patients with confirmed Celiac Disease and healthy control groups, ii) specificity-based screening of bacterial display peptide libraries against pooled serum antibody and total serum protein depleted of HSA and IgG/IgA, iii) identification of library selected clones for diagnostic array construction, and iv) training of the array to maximize diagnostic specificity and sensitivity relative to the control group. The diagnostic array will then be validated with an undiagnosed patient group presenting the symptoms of CD. PUBLIC HEALTH RELEVANCE: Existing methodologies for interrogating the diverse antibody specificities present in the circulating repertoire have yielded new insights and diagnostics for autoimmune diseases and cancer. The proposed approach could expand these capabilities providing greater information about disease pathology, and allowing for the generation of improved biochemical reagents to create more effective yet inexpensive diagnostic tests. This work will establish a new gold standard methodology for analysis of serum antibody specificities, as well as provide reagents to diagnose a common autoimmune disorder (Celiac Disease), and better understand its cause.